(a) Technical Field
The present Invention relates to an apparatus for warning a vehicle driver of danger of doze-off driving, in which driver's distraction caused by drowsiness is determined based on time of closure/open of driver's eye.
(b) Technical Background
Recently, the death toll by traffic accidents increases in substantially proportion to increase of vehicles. In order to decrease the death toll by traffic accidents, various efforts are made to develop advanced safety vehicle (ASV) all over the world. The ASV is designed to provide a driver with comfort, to decrease death toll by traffic accidents, and to be easy to drive as well. A basic concept of the ASV is to prevent accidents in advance such that safety of pedestrians and the vehicle itself can be ensured. Examples of technologies employed in the ASV include a doze-off state detection system, a night obstacle detection system, and a warning system of distance between cars.
Japanese Patent Application Publication No. H11-339200 teaches a doze-off state detection system in which frequency of eyeblink of the driver, speed of eyeblink of the driver, open degree of the eye, and time of closure of the eye are used as criteria to determine drowsiness.
Moreover, Japanese Patent Application Publication No. H09-277849 teaches another system in which time of eyeblink of a driver is detected and frequency distribution of the detected eyeblink time is used to determine the degree of decrease of the driver's attention.
Moreover, Japanese Patent No. 3509839 discloses an apparatus for estimating the degree of driver's attention based on a value of drowsiness calculated on the basis of horizontal movement of driver's eyeball and a ratio of the number of long time eyeblink to the total number of eyeblink for a predetermined time period.
There is, however, an individual deviation in the correlation between the time and frequency of eyeblink and the degree of doze-off.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.